This video explores aphasia, a disorder that affects language and communication due to brain injury. It explains the different types of aphasia, their symptoms, and the brain areas involved, such as Broca's and Wernicke's areas. The video also highlights the brain's adaptability in supporting language functions despite damage.

Language is an essential part of our lives that we often take for granted. With it, we can communicate our thoughts and feelings, lose ourselves in novels, send text messages, and greet friends. It's hard to imagine being unable to turn thoughts into words. But if the delicate web of language networks in your brain became disrupted by stroke, illness, or trauma, you could find yourself truly at a loss for words. This disorder, called aphasia, can impair all aspects of communication. People who have aphasia remain as intelligent as ever. They know what they want to say but can't always get their words to come out correctly. They may unintentionally use substitutions called paraphasias, switching related words like saying "dog" for "cat," or words that sound similar, such as "house" for "horse." Sometimes, their words may even be unrecognizable. There are several types of aphasia, grouped into two categories: fluent, or receptive aphasia, and non-fluent, or expressive aphasia. People with fluent aphasia may have normal vocal inflection but use words that lack meaning. They have difficulty comprehending the speech of others and are frequently unable to recognize their own speech errors. People with non-fluent aphasia, on the other hand, may have good comprehension but will experience long hesitations between words and make grammatical errors. We all have that tip-of-the-tongue feeling from time to time when we can't think of a word. But having aphasia can make it hard to name simple, everyday objects. Even reading and writing can be difficult and frustrating. So how does this language loss happen? The human brain has two hemispheres. In most people, the left hemisphere governs language. We know this because, in 1861, the physician Paul Broca studied a patient who lost the ability to use all but a single word, "tan." During a post-mortem study of that patient's brain, Broca discovered a large lesion in the left hemisphere, now known as Broca's area. Scientists today believe that Broca's area is responsible in part for naming objects and coordinating the muscles involved in speech. Behind Broca's area is Wernicke's area, near the auditory cortex. That's where the brain attaches meaning to speech sounds. Damage to Wernicke's area impairs the brain's ability to comprehend language. Aphasia is caused by injury to one or both of these specialized language areas. Fortunately, there are other areas of the brain which support these language centers and can assist with communication. Even brain areas that control movement are connected to language. fMRI studies found that when we hear action words like "run" or "dance," parts of the brain responsible for movement light up, as if the body was actually running or dancing. Our other hemisphere contributes to this.